Latching mechanism for electric switches



Jan. 24, 1950 B. JOCHEM ETAL 2,495,330

LATCHING MECHANISM FOR ELECTRIC SWITCHES Filed Jan. 17, 1945 PatentedJan. 24, 1950 UNITED ST Es PATENT OFFICE .LA'romN MECHANISM FOR ELECTRICSWITCHES Theodore B. Jochem; Edwin W. Seeger, and Palmer T; Severson,Wauwatosa, 'Wis., assignnrs ito Gntler-Hammer, Inc., Milwaukee,'Wis.,:a-. corporation of Delaware Application January 17, 1945, SerialNesta-1,82

4 Claims.

'I-h-is invention relates "to electricsw-itches and more particularly toshock-proof switches of theknifeblade'type.

The present invention has among its objectsto' provide a shock-proofknife switch which meets the requirements ofnavy service, or in otherwords, a knife switch which remains open or closed when subjected tohigh shock in any direction.

Another object is to provide a simple, ruggedmechanism which can be andreliable latching readily applied to a knife blade switch to hold thesame in closed position against the action of shocks or jar-ringrorcestowhich the switch maybe subjected.

Another object is to -provide a latching-"mechanism of the aforesaidtype which-operates to automatically locktheswitchwhen the same tible ofmodification without departing from. the

spirit and scope oftheappended. claims. In the drawing,

Figural is a front elevaiional view of arknife switch embodying theinvention;

Fig. 2 is. aside view and Fig. Bjis a topview of the switch-shownin Fig.1, and

Fig. 4 .is aseotional view on lined-4 of=xFig;. 3

Beierringfto .Figs. 1 the same illustrate aiknife switch includinga.pair ofblades I-r-I, each of. whichnhas a lower-hinge jaw 2; endan uppercontact jaw.3.associated therewith. The hinge jaws 2 and contact. jaws,3 are mounted upon vertically disposed insulating panel 4, and eachofthe blades I is pivotally secured :toi-tsassociated hing-ejaw .2byabolt-d; The free ends of blades I are securedato an insnlatingtieber6 which carriesan operatinghamlle I. Tie-bar 5 also carries a latch 8which cooperates with a stationary stop pin 9 to lock blades I inengagement with their associated contact jaws 3. As hereinafter setforth, latch 8 is releasable from pin 9 by rotative movement of handle Ito permit disengagement of blades I from their associated contact jaws 3and said handle and latch are constructed and. arranged to insureagainst unlocking of the switch under high shock conditions.

More specifically, handle I and latch 8 are,

mounted upon an insulating block IB which is secured to the upper sideof tie bar 6 by screws II. Operating handle I is mounted between theside arms of a horizontally disposed 'U-shaped.

bracket I2 upon -a'pi-n-I3. The connecting. portion :I 4 of bracket I2is rotatably supported upon i the front face of block- -I'0- by a pivot'pin 15 and as shown in Fig. 4 said pin is fixed to said bracket andisrotatably supported and held against axial movement within an openingin block I0. Pivot pin. 15 is located midway between the side arms of"bracket I12 wherebysaid bracket and handle I are balanced upon said pin.

Latch :8 is disposed at right angles to tie hat 6 and is pivotallysupported within aslot formed :in'the underside of-bloc-k I=Il upon ahorizontally disposed pin l t. The rear end of latch 8 is provided witha downwardly extending hookprojection. II forengaging stop pin 9 and"the front;

end thereof'projects beyondblock I0 for-engagementwithcam-surfacesIBformed by a -V-shaped recess I9 in the under side of the connectingportion I l of bracket 12. Pivot pin I6 is located so that Ilatch 8is-balanced thereon, and said latch is biased .by a spring 20 tomaintain the front .:end thereof in engagement with the cam surfaces I8;

Stop pin 9 is carried by aninsulating block 24 which is securedito panelI by bolts 22. Block H is recessed to. receive the rear end of latch- 8and the front end of said block serves as a.

stop for tie bar 6 to limit inward movement of blades I with respect totheir associated contact jaws 3.

In connection with the foregoing it will be E noted that the front .end,of latch 8 is held by spring, 20 in engagement with; the cam surfaces:

I8 -to normally hold bracket I2 and handle I in the horizontal positionshown .in Fig. 1. With handle I in this-position the hook projection I"!of latch 8 is movedinto locking engagement with stop pin 9, as shown inFig. 2, tolock bladesI When-,the-Esame are moved into full -engagementwith their .associatedcontaot jaws 3. As is apparent from Fig. 1, uponrotation of handle I in either direction out of its normal horizontalposition one or the other of the cam surfaces I8 operates to move thefront end of latch 8 downwardly against the action of spring 20. Thehook projection I1 is thus moved out of engagement with stop pin 9 topermit opening of the switch by a forward pull on operating handle 1. Ashereinbefore set forth, latch 8 is balanced upon its associated pivotpin I6 and handle 1 and bracket I2 are balanced upon their associatedpivot pin I5. These parts therefore do nottend to rotate under theaction of accelerating forces ca sed by shock. Thus when the switch isin closed position as shown in Fig. 2, spring 20 opera'tes to maintainlatch 8 in engagement with stop pin 9 and to also prevent movement ofhandle 1 out of its normal horizontal position to thereby preventunlocking of the switch under shock conditions.

As shown in Figs. 1 and 2, each of the hinge jaws 3 carries a stop pin23. These stop pins cooperate with stop surfaces 24 on the lower ends ofknife blades I to limit opening movement of said blades beyond thedotted line position shown in Fig. 2. It will be noted that the stoppins 23 are located as close as possible to pivot bolts 5 so that forcesresulting from shock are transmitted from said stop pins to blades Ithrough relatively short lever arms to insure against movement of saidblades into circuit closing position under shock conditions.

What we claim as new and desire to secure by Letters Patent is:

1. A shock-proof knife switch comprising a blade element pivoted at oneend, a front operating handle mounted upon the free end of said bladeelement for movement therewith, said handle being pivoted upon saidblade element to permit rotative movement thereof in a plane at rightangles to the direction in which the same is moved for operation of saidblade element, a latch pivotally mounted upon the free end of said bladeelement, and a stationary catch to be engaged by said latch for lockingof said blade element when the same is moved into circuit closingposition, said latch being releasable from said catch by rotativemovement of said handle, and said handle and said latch being staticallybalanced upon their associated pivots to insure against release of saidlatch from said catch under the action of accelerating forces caused byshock.

2. A shock-proof knife switch comprising a blade element pivoted at oneend, a latch pivotally mounted upon the free end of said blade element,a stationary catch to be engaged by said latch for locking of said bladeelement when the same is moved into circuit closing position, a frontoperating handle mounted upon the free end of said blade element formovement therewith, said handle being pivoted upon said blade element topermit rotative movement thereof in a plane at right angles to thedirection in which the same is moved for operation of said bladeelement, and a cam associated with said operating handle for releasingsaid latch upon rotative movement of said handle, said handle and saidlatch being statically balanced upon their a sociated pivots to insureagainst release of said 1 ch from said catch under the action ofaccelerating forces caused by shock.

3. The combination with a knife switch including movable conductingblades pivoted at one end and having a tie bar extending between thefree ends thereof, of a stationary locking part, a latch mounted uponsaid tie bar to move therewith and adapted to engage said locking partto lock said blades in circuit closing position, said latch beingpivoted upon said tie bar to permit. release thereof from said lockingpart, a spring associated with said latch for yieldingly maintaining thesame in looking engagement with said locking part, and a switchoperating handle carried by said tie bar and pivoted thereon to permitrotative movement thereof, said latch being releasable from said lockingpart by rotative movement of said operating handle,

and said latch and said handle being statically" balanced upon theirassociated pivots to insure against release of said latch from saidlocking part under the action of accelerating forces caused by shock.

4. The combination with a knife switch including conducting bladespivoted at one end and having a tie bar extending between the free endsthereof, of a stationary locking part, a spring biased pivoted latchmounted upon said tie bar to move therewith and adapted to engage saidlocking part to lock said blades in circuit closing position, and aswitch operating handle carriedby said tie bar and pivoted thereon topermitrotative movement thereof, said operating handle having a camassociated therewith which cooperates with said latch to normallymaintain said operating handle in a given angular position and whichalso acts upon rotative movement of a said operating handle out of saidnormal position to effect release of said latch from said locking part,said operating handle and said latch being statically balanced upontheir associated pivots to insure against release of said latch fromsaid locking part under the action of accelerating forces caused byshock.

THEODORE B. JOCHEM. EDWIN W. SEEGER. PALMER 'I'. SEVERSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 770,818 Nemmert Sept. 27, 1904847,087 Liden Mar. 12, 1907 1,229,703 Baxter June 12, 1917 1,322,065Sessions Nov. 18, 1919 2,224,380 Crabbs et al Dec. 10, 1940 2,266,994Saunders Dec. 23, 1941 2,385,304 Schymik Sept. 18, 1945 2,418,470 HarlowApr. 8, 1947 FOREIGN PATENTS Number Country Date 2,594 Great BritainJune 15, 1911 229,259 Great Britain Apr. 23, 1925 298,306 Germany Oct.6, 1920

